/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.apache.tomcat.util.bcel.classfile;

import java.io.DataInput;
import java.io.IOException;

public abstract class ElementValue {
	public static final byte STRING = 's';
	public static final byte ENUM_CONSTANT = 'e';
	public static final byte CLASS = 'c';
	public static final byte ANNOTATION = '@';
	public static final byte ARRAY = '[';
	public static final byte PRIMITIVE_INT = 'I';
	public static final byte PRIMITIVE_BYTE = 'B';
	public static final byte PRIMITIVE_CHAR = 'C';
	public static final byte PRIMITIVE_DOUBLE = 'D';
	public static final byte PRIMITIVE_FLOAT = 'F';
	public static final byte PRIMITIVE_LONG = 'J';
	public static final byte PRIMITIVE_SHORT = 'S';
	public static final byte PRIMITIVE_BOOLEAN = 'Z';
	private final int type;
	private final ConstantPool cpool;
	ElementValue(final int type, final ConstantPool cpool) {
		this.type = type;
		this.cpool = cpool;
	}

	public static ElementValue readElementValue(final DataInput input, final ConstantPool cpool) throws IOException {
		final byte type = input.readByte();
		switch (type) {
			case PRIMITIVE_BYTE:
			case PRIMITIVE_CHAR:
			case PRIMITIVE_DOUBLE:
			case PRIMITIVE_FLOAT:
			case PRIMITIVE_INT:
			case PRIMITIVE_LONG:
			case PRIMITIVE_SHORT:
			case PRIMITIVE_BOOLEAN:
			case STRING:
				return new SimpleElementValue(type, input.readUnsignedShort(), cpool);

			case ENUM_CONSTANT:
				input.readUnsignedShort();    // Unused type_index
				return new EnumElementValue(ENUM_CONSTANT, input.readUnsignedShort(), cpool);

			case CLASS:
				return new ClassElementValue(CLASS, input.readUnsignedShort(), cpool);

			case ANNOTATION:
				// TODO isRuntimeVisible
				return new AnnotationElementValue(ANNOTATION, new AnnotationEntry(input, cpool), cpool);

			case ARRAY:
				final int numArrayVals = input.readUnsignedShort();
				final ElementValue[] evalues = new ElementValue[numArrayVals];
				for (int j = 0; j < numArrayVals; j++) {
					evalues[j] = ElementValue.readElementValue(input, cpool);
				}
				return new ArrayElementValue(ARRAY, evalues, cpool);

			default:
				throw new ClassFormatException(
						"Unexpected element value kind in annotation: " + type);
		}
	}

	public abstract String stringifyValue();

	final ConstantPool getConstantPool() {
		return cpool;
	}

	final int getType() {
		return type;
	}
}
